Craig, it seems the minimal conductor spacing conforming 6.3 (table 6-1) prevents shorts as a result of contamination, delamination, conductive particles, etching imperfections (crest and overhang). Such imperfections would faciliate shorts independent of the base material. Bernhard Wanner ---------- Von: Craig Hillman[SMTP:[log in to unmask]] Gesendet: Freitag, 18. Juni 1999 12:00 An: [log in to unmask] Betreff: [TN] IPC-2221 Table 6.1 Conductor Spacing I was wondering if anyone could provide me with information on the research used to determine the conductor spacing requirements of IPC-2221. More specifically, why is it not material dependent and is there a safety factor provided in the spacing determination? Any help would be greatly appreciated. Thanks in advance, Craig Hillman University of Maryland Dr. Craig Hillman CALCE Electronic Products and Systems Consortium University of Maryland College Park, MD 20742 (301)-405-5316 [log in to unmask]